The present invention relates to a heating holder for an electron microscope.
In conventional electron microscopes, a sample to be observed is formed in a shape of a disk having a diameter of 3 mm near the center of which a hole is bored, and a portion near the hole having a thickness capable of transmitting an electron beam is observed. However, it is impossible to exactly control position of the hole. In regard to heating method, the sample is heated by a heater arranged circularly along the outer periphery of the disk. A problem of the heating method is that the heating portion and the observed portion are distant from each other and temperature of the sample cannot be guaranteed. In addition to this, prevention of leakage of heat becomes more difficult as heating temperature is increased. Although there is a method of preventing the heat leakage by covering all over the heating portion, the heating stage becomes so large in size that characteristic of the electron microscope is limited by occurrence of troubles in its double tilting function and element analysis. Further, measures against deposition of a sample to the heater due to melting of the sample caused by overheating, and the main body of the heating holder has to be exchanged in some cases.
Further, as a means to observe a high resolution image at a high temperature there is a method in which fine powder of a sample is sprinkled on a tungsten filament and heated by directly passing current through the tungsten filament. However, it cannot be guaranteed that the image shows a real characteristic of the sample in form of bulk since the sample is fine powder.
Sample holders for electron microscope known are disclosed in U.S. Pat. No. 5,296,669 and U.S. Pat. No. 5,367,171.
Japanese Patent Application Laid-Open No. 6-44936 discloses a heater for heating a sample which is wound in a coil shape and placed horizontal, and the sample is placed in the coil.
Further, Japanese Patent Application Laid-Open No. 6-68828 discloses a flat-shaped ceramic heater as a heater for heating a sample.
Any one of the heaters for heating a sample disclosed in these patent specifications cannot stably set the sample, and cannot efficiently heat the sample.
A problem to be solved by the present invention is to make it possible to observe a high resolution image of a sample in form of bulk at a high temperature up to 1800.degree. C., which cannot be performed by the above-mentioned conventional technology, and to make it possible to always heat a sample under a clean environment by easily detaching its heating stage when the heating stage is damaged by deposition of the sample to the heating stage through the high-temperature observation.